In minimally invasive medical interventions needles, guide wires, sheaths and catheters are inserted in the patient in order to find and measure, on the one hand, the relevant anatomy of the patient and treat or place a stent (for example) on the other hand. Clearly, the part of the devices inserted into the patient either must be sterile at all times or should only be contaminated with fluids and tissue from the patient itself. When a needle, guide wire or catheter is armed with a sensor or actuator, some connection (for example electrical wire or optical fiber) must be made to transmit the information or power to or from a controller or interrogator placed in the non-sterile zone, away from the patient. Somewhere along the transmission line, the sterile zone meets the non-sterile zone. This setup requires proper management of sterility.
The use of optical interrogation techniques in minimally invasive medical interventions requires that, on the one hand, the optical sensor is inserted in the patient and must be sterile and, on the other hand, that the optical waveguide that transmits the optical information is plugged into a mating sleeve of a patch cord, controller or interrogator placed in the non-sterile zone, away from the patient. Upon making the optical connection, the sterile proximal end of the optical sensor comes in contact with the non-sterile patch cord, controller or interrogator thereby also becoming non-sterile. During a medical procedure a sterility problem may arise in case the optical waveguide needs to be disconnected and the (now non-sterile) proximal end of the medical device containing the optical sensor needs to enter the sterile zone or when devices have to slide over the medical device containing the optical sensor. The latter is for example the case when a so-called back-loadable guide wire armed with optical shape sensing (OSS) is used. In essence, whenever the proximal end of a guide wire becomes non-sterile, the next device (a catheter or stent) that slides over it will transport the contamination into the body of the patient.
U.S. Pat. No. 5,949,929 discloses an interventional medical device having a rotatable optical fiber, an assembly having a conduit for conveying a light beam to the rotatable fiber as well as a rotor and a fixed housing, and a coupling. The coupling includes a rotatable portion attachable to a proximal end of the rotatable fiber and to the rotor so as to permit the rotatable fiber to rotate continuously with the rotor while the rotatable fiber remains in axial alignment with the light beam. The proximal end of the rotatable portion of the coupling has a V-shaped coupling surface that complements a distal end surface of the rotor. In some embodiments, a GRIN (gradient index of refraction) lens is arranged between the stationary optical fiber and the rotatable optical fiber which reduces the need for precise alignment of the optical fibers.